This invention relates to a heat-sensitive recording material and more particularly it relates to a heat-sensitive recording material which comprises a support sheet of 5-40.mu. in thickness having thereon a heat-sensitive transfer layer containing a phenolic material, a colorless or pale-colored chromogenic material which reacts with said phenolic material to form color upon application of heat and a heat fusible material having a melting point of 40.degree.-150.degree. C. and an image receiving sheet superposed on the surface of said layer which are made into one integral sheet by pressing. According to this invention there is provided a method for obtaining a fixed heat-sensitive recorded image which comprises heating said recording material from the side of said support sheet of 5-40.mu. in thickness by a thermal pen, a thermal head or infra-red radiation and thereafter separating the two sheets to transfer the heat-imprinted portion to the image receiving sheet. Heat-sensitive recording sheets which use a chromogenic material such as Crystal Violet Lactone and a phenolic material such as bisphenol A in combination are disclosed in, for example, Japanese Patent After-examination Publication (KOKOKU) No. 14039/70. Such heat-sensitive recording sheets are now widely used as business copying papers, recording papers of various recorders, electrocardiographs, in desk-top calculator, terminals of computer, facsimiles, etc.
However, when these heat-sensitive recording sheets are carelessly heated after imprinting, it is liable to occur that the background of the sheet forms color and the imprinted letters become unreadable or are altered. Thus, solution of such defects has been strongly desired. Japanese Patent After-examination Publication (KOKOKU) No. 2534/76 and Japanese Patent Pre-examination Publication (KOKAI) No. 22134/72 proposed heat-sensitive recording methods which overcome said defects, according to which two heat-sensitive components are on separate sheets and letters are imprinted in such state that the coating layers are in contact with each other. Furthermore, Japanese Patent After-examination Publication (KOKOKU) No. 43788/76 proposed a method according to which colored dyes or pigments are contained in a heat-sensitive transfer layer and letters are imprinted thereon in such state wherein the heat-sensitive transfer layer and an ordinary paper are superposed. However, when the two sheets are merely superposed as in these methods, the two sheets are liable to shift in relation to each other or thermal conductivity is very low and sufficient recording density cannot be obtained under such limited heat energies as thermal printers, thermal facsimiles, and the like.
Furthermore, Japanese Patent Pre-examination Publications (KOKAI) No. 45938/72 and No. 48137/73 and Japanese Patent After-examination Publication (KOKOKU) No. 29949/76 proposed methods according to which a heat-sensitive transfer layer is formed from waxes or resins of low molecular weight, colored dyes are dissolved or dispersed in said layer and this layer is allowed to contact an ordinary paper. However, in this case a part of the layer is apt to transfer to the ordinary paper to cause staining of background and to decrease contrast between letters and the background. Thus, the recorded letters cannot be easily read. Moreover, appearance of the letters is not good and commercial value is greatly reduced.